U.S. patent application number 13/054574 was filed with the patent office on 2011-05-26 for backlight device and display device provided with the same.
This patent application is currently assigned to SHARP KABUSHIKI KAISHA. Invention is credited to Masakazu Komano.
Application Number | 20110122651 13/054574 |
Document ID | / |
Family ID | 41721173 |
Filed Date | 2011-05-26 |
United States Patent
Application |
20110122651 |
Kind Code |
A1 |
Komano; Masakazu |
May 26, 2011 |
BACKLIGHT DEVICE AND DISPLAY DEVICE PROVIDED WITH THE SAME
Abstract
Provided is a backlight device which can suppress deterioration
of uniformity. The backlight device (10) is provided with an LED
(11), and a light guide plate (12) which includes a light incoming
surface (12a) and a light outgoing surface (12b). An inclined
surface (12c) which is inclined from the light outgoing surface is
formed between the light incoming surface and the light outgoing
surface of the light guide plate, and the light guide plate is
formed such that the thickness of a portion on the light incoming
surface side is more than that of a portion on the light outgoing
surface side. At the front of the portion on the light incoming
surface side of the light outgoing surface of the light guide
plate, a regulating member (13), which has a light blocking
characteristic and regulates shift of the light guide plate in the
thickness direction of the light guide plate, is arranged.
Inventors: |
Komano; Masakazu;
(Osaka-shi, JP) |
Assignee: |
SHARP KABUSHIKI KAISHA
Osaka-shi, Osaka
JP
|
Family ID: |
41721173 |
Appl. No.: |
13/054574 |
Filed: |
May 15, 2009 |
PCT Filed: |
May 15, 2009 |
PCT NO: |
PCT/JP2009/059038 |
371 Date: |
January 18, 2011 |
Current U.S.
Class: |
362/611 ;
362/615; 362/618; 362/633 |
Current CPC
Class: |
G02B 6/002 20130101;
G02F 1/133308 20130101; G02B 6/0031 20130101; G02B 6/0091 20130101;
G02F 1/133322 20210101; G02B 6/009 20130101; G02F 1/133615
20130101; G02B 6/0083 20130101 |
Class at
Publication: |
362/611 ;
362/615; 362/633; 362/618 |
International
Class: |
F21V 8/00 20060101
F21V008/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 29, 2008 |
JP |
2008-220916 |
Claims
1. A backlight device of a sidelight type, comprising: a
light-emitting element; a light guide plate that includes a light
incidence surface on which light from the light-emitting element
becomes incident and a light output surface from which incident
light is outputted to a side of a display panel; and an optical
sheet that is disposed in opposition to the light output surface of
the light guide plate, wherein an inclined surface inclined with
respect to the light output surface is formed between the light
incidence surface and the light output surface of the light guide
plate, the light guide plate is formed so as to have a thickness
larger at a portion on a side of the light incidence surface than
at a portion on a side of the light output surface, and a
restriction member that has a light-blocking property and restricts
the light guide plate from being moved in a thickness direction of
the light guide plate is disposed forward of a portion of the light
output surface of the light guide plate on a side of the light
incidence surface.
2. The backlight device according to claim 1, further comprising: a
frame that houses the light-emitting element, the light guide
plate, and the optical sheet; and an adhesive member for fixing the
display panel to the frame, wherein the restriction member is
bonded to the adhesive member.
3. The backlight device according to claim 1, further comprising: a
resinous frame that houses the light-emitting element, the light
guide plate, and the optical sheet, wherein the restriction member
is formed integrally with the frame.
4. The backlight device according to claim 1, wherein the
restriction member is fixed to the optical sheet.
5. The backlight device according to claim 4, wherein the optical
sheet comprises a diffusion sheet disposed in contact with the
light output surface of the light guide plate, and the restriction
member is fixed to the diffusion sheet.
6. The backlight device according to claim 1, wherein the
restriction member is formed by bonding a wide sheet member
disposed forward of the light incidence surface and the light
output surface of the light guide plate to a narrow sheet member
disposed forward of the light output surface of the light guide
plate.
7. The backlight device according to claim 6, further comprising: a
frame that houses the light-emitting element, the light guide
plate, and the optical sheet, wherein the frame has a function of
preventing the wide sheet member of the restriction member from
being moved in a plane direction of the wide sheet member.
8. The backlight device according to claim 1, wherein the
restriction member has a function of reflecting light.
9. The backlight device according to claim 1, further comprising: a
frame that houses the light-emitting element, the light guide
plate, and the optical sheet; and an adhesive member for fixing the
display panel to the frame, wherein at least part of the adhesive
member is disposed forward of the light incidence surface of the
light guide plate, and a distance between the light output surface
of the light guide plate or the optical sheet and the restriction
member is smaller than a distance between the portion of the light
guide plate on the side of the light incidence surface and the
adhesive member.
10. The backlight device according to claim 1, wherein the
light-emitting element comprises: a light-emitting chip; a package
main body portion that has a concave portion for housing the
light-emitting chip; and a filler that is filled in the concave
portion of the package main body portion so as to cover the
light-emitting chip, and the light incidence surface of the light
guide plate is formed so as to extend to a position more forward
than the concave portion of the package main body portion.
11. A display device, comprising: the backlight device according to
claim 1; and a display panel that is illuminated by the backlight
device.
12. A display device, comprising: the backlight device according to
claim 2; and a display panel that is illuminated by the backlight
device.
13. A display device, comprising: the backlight device according to
claim 3; and a display panel that is illuminated by the backlight
device.
14. A display device, comprising: the backlight device according to
claim 4; and a display panel that is illuminated by the backlight
device.
15. A display device, comprising: the backlight device according to
claim 5; and a display panel that is illuminated by the backlight
device.
16. A display device, comprising: the backlight device according to
claim 6; and a display panel that is illuminated by the backlight
device.
17. A display device, comprising: the backlight device according to
claim 7; and a display panel that is illuminated by the backlight
device.
18. A display device, comprising: the backlight device according to
claim 8; and a display panel that is illuminated by the backlight
device.
19. A display device, comprising: the backlight device according to
claim 9; and a display panel that is illuminated by the backlight
device.
20. A display device, comprising: the backlight device according to
claim 10; and a display panel that is illuminated by the backlight
device.
Description
TECHNICAL FIELD
[0001] This invention relates to a backlight device and a display
device provided with the same, and relates particularly to a
sidelight type backlight device and a display device provided with
the same.
BACKGROUND ART
[0002] There is conventionally known a sidelight type backlight
device (see, for example, Patent Document 1).
[0003] Patent Document 1 mentioned above discloses a backlight
structural body (backlight device) of a sidelight type (referred to
also as an edge-light type) including a light guide plate as well
as an LED light source and a reflective structure that are disposed
on a lateral side of the light guide plate.
[0004] In this backlight structural body, the light guide plate is
formed so that its light incidence surface and its light output
surface are orthogonal to each other. Light outputted from the LED
light source becomes incident on the light incidence surface of the
light guide plate by being reflected by the reflective structure
and then is outputted from the light output surface.
[0005] There is also conventionally known a sidelight type
backlight device including a light guide plate having an inclined
surface inclined with respect to a light output surface.
[0006] FIG. 10 is a cross-sectional view showing the structure of a
display device provided with a sidelight type backlight device
according to a conventional example. As shown in FIG. 10, a display
device 501 provided with a sidelight type backlight device 510
according to a conventional example includes a display panel 502,
an upper polarization plate 503 and a lower polarization plate 504
sandwiching the display panel 502 therebetween, the backlight
device 510 disposed on a back surface side (lower side) of the
display panel 502, and a metal frame 505 covering a back surface
side portion of the backlight device 510.
[0007] The display panel 502 includes two transparent substrates
502a and 502b. Liquid crystal, which is not shown, is sealed in
between the two substrates 502a and 502b. Furthermore, a driving IC
(integrated circuit) 506 and an FPC (flexible printed circuit) 507
are attached to the front surface of the substrate 502a. The FPC
507 is bent at a predetermined position thereof so as to be
disposed also on a back surface side of an after-mentioned frame
515.
[0008] The backlight device 510 includes a plurality of LEDs 511, a
light guide plate 512 having a light incidence surface 512a on
which light from the LEDs 511 becomes incident, a plurality of
optical sheets 513 disposed in opposition to a light output surface
512b of the light guide plate 512, a reflection sheet 514 disposed
on a back surface side of the light guide plate 512, and the
frame-shaped frame 515 that houses these components.
[0009] The plurality of LEDs 511 are fixed to the FPC 507 via a
solder layer 516 and disposed so as to be opposed to the light
incidence surface 512a of the light guide plate 512.
[0010] A portion of the FPC 507, which is disposed on the back
surface side of the frame 515, is bonded to the frame 515 by use of
an adhesive member 517 made of a double-sided adhesive tape or the
like.
[0011] The light guide plate 512 is formed so that the light
incidence surface 512a and the light output surface 512b are
substantially orthogonal to each other. Furthermore, an inclined
surface 512c inclined at an angle .theta. 101 (e.g. 6.degree.) with
respect to the light output surface 512b is formed between the
light incidence surface 512a and the light output surface 512b of
the light guide plate 512. That is, the light guide plate 512 is
formed so as to have a thickness larger at a portion on the side of
the light incidence surface 512a (side of the LEDs 511) than at a
portion on the side of the light output surface 512b.
[0012] Furthermore, the light guide plate 512 is disposed at a
predetermined distance from an after-mentioned adhesive member
518.
[0013] The plurality of optical sheets 513 are composed of a
diffusion sheet 513a, a lower lens sheet 513b, and an upper lens
sheet 513c.
[0014] The frame 515 is bonded to the display panel 502 by use of
the adhesive member 518 made of a double-sided adhesive tape or the
like.
[0015] In the backlight device 510, as described above, the light
guide plate 512 is formed so as to have a thickness larger at the
portion on the side of the light incidence surface 512a (side of
the LEDs 511) than at the portion on the side of the light output
surface 512b, and thus an increased proportion of light outputted
from the LEDs 511 can be made incident on the light guide plate
512.
[0016] Furthermore, the light guide plate 512 can be made thinner
at the portion thereof on the side of the light output surface
512b, and thus the backlight device 510 (display device 501) as a
whole can be reduced in thickness.
[0017] Furthermore, in the backlight device 510, since the light
guide plate 512 is disposed at a predetermined distance from the
adhesive member 518, it is possible to prevent light incident on
the light guide plate 512 from being outputted to the side of the
adhesive member 518 to be absorbed by the adhesive member 518. If
the light guide plate 512 is bonded to the adhesive member 518,
light incident on the light guide plate 512 is likely to be
outputted from a portion of the light guide plate 512 where the
light guide plate 512 is bonded to the adhesive member 518. Light
outputted from the light guide plate 512 then is absorbed by the
adhesive member 518. Because of this, if the light guide plate 512
is bonded to the adhesive member 518, light use efficiency is
deteriorated, which leads to a decrease in the luminance of the
display panel 502.
LIST OF CITATIONS
Patent Literature
[0018] Patent Document 1: JP-A-2007-41605
SUMMARY OF THE INVENTION
Technical Problems
[0019] In the display device 501 provided with the backlight device
510 according to the conventional example, however, since the
inclined surface 512c inclined with respect to the light output
surface 512b is formed on the light guide plate 512, part of light
incident on the light guide plate 512 is outputted from the
inclined surface 512c to the side of the display panel 502. This
leads to a disadvantage that the display panel 502 exhibits a high
(increased) luminance at a portion thereof in the vicinity of the
LEDs 511 compared with a luminance at a portion thereof other than
the vicinity of the LEDs 511. That is, there is a problem that the
uniformity ratio is deteriorated.
[0020] Furthermore, in the display device 501, since the light
guide plate 512 is disposed at a predetermined distance from the
adhesive member 518, the light guide plate 512 is movable in the
thickness direction. This leads to a disadvantage that, at the time
of assembly or the like, the light guide plate 512 as a whole may
become inclined with respect to the display panel 502. If the light
guide plate 512 as a whole becomes inclined with respect to the
display panel 502 as described above, there arises a disadvantage
that the display panel 502 exhibits a high luminance at a portion
thereof on the side of the LEDs 511 (a low luminance at a portion
thereof on the side opposite to the LEDs 511), or a low luminance
at the portion thereof on the side of the LEDs 511 (a high
luminance at the portion thereof on the side opposite to the LEDs
511). Because of this, there is a problem that the uniformity ratio
is further deteriorated.
[0021] In order to solve the above-described problems, it is an
object of this invention to provide a backlight device that can
suppress deterioration in uniformity ratio, and a display device
provided with the same.
Solution to the Problems
[0022] In order to achieve the above-described object, a backlight
device according to a first aspect of this invention is a sidelight
type backlight device and includes: a light-emitting element; a
light guide plate that includes a light incidence surface on which
light from the light-emitting element becomes incident and a light
output surface from which incident light is outputted to the side
of a display panel; and an optical sheet that is disposed in
opposition to the light output surface of the light guide plate. In
the backlight device, an inclined surface inclined with respect to
the light output surface is formed between the light incidence
surface and the light output surface of the light guide plate.
Further, the light guide plate is formed so as to have a thickness
larger at a portion on the side of the light incidence surface than
at a portion on the side of the light output surface, and a
restriction member that has a light-blocking property and restricts
the light guide plate from being moved in the thickness direction
of the light guide plate is disposed forward of a portion of the
light output surface of the light guide plate on the side of the
light incidence surface.
[0023] In this backlight device according to the first aspect, as
described above, the restriction member having a light-blocking
property is disposed forward of the portion of the light output
surface of the light guide plate on the side of the light incidence
surface. Thus, even in a case where part of light incident on the
light guide plate is outputted from the inclined surface to the
side of the display panel, the restriction member having a
light-blocking property can prevent light outputted from the light
guide plate from reaching the display panel. This can prevent a
phenomenon in which the display panel exhibits a high (increased)
luminance at a portion thereof in the vicinity of the
light-emitting element compared with a luminance at a portion
thereof other than the vicinity of the light-emitting element. As a
result, deterioration in uniformity ratio can be suppressed.
[0024] Furthermore, in the backlight device according to the first
aspect, as described above, the restriction member that restricts
the light guide plate from being moved in the thickness direction
of the light guide plate is disposed forward of the portion of the
light output surface of the light guide plate on the side of the
light incidence surface, and thus the light guide plate can be
prevented from being moved in the thickness direction. This can
prevent the light guide plate as a whole from being inclined with
respect to the display panel, and thus a phenomenon can be
prevented in which the display panel exhibits a high luminance at a
portion thereof on the side of the light-emitting element (a low
luminance at a portion thereof on the side opposite to the
light-emitting element), or a low luminance at the portion thereof
on the side of the light-emitting element (a high luminance at the
portion thereof on the side opposite to the light-emitting
element). As a result, deterioration in uniformity ratio can be
further suppressed.
[0025] Furthermore, in the backlight device according to the first
aspect, as described above, the light guide plate is formed so as
to have a thickness larger at the portion on the side of the light
incidence surface than at the portion on the side of the light
output surface, and thus the area of the light incidence surface
can be increased. Thus, an increased proportion of light outputted
from the light-emitting element can be made incident on the light
guide plate, so that improved luminance can be obtained.
[0026] Furthermore, in the backlight device according to the first
aspect, as described above, the light guide plate is formed so as
to have a thickness larger at the portion on the side of the light
incidence surface than at the portion on the side of the light
output surface, and thus the light guide plate can be made thinner
at the portion thereof on the side of the light output surface,
thereby allowing a reduction in the thickness of the backlight
device as a whole.
[0027] In the above-described backlight device according to the
first aspect, preferably, there are further provided: a frame that
houses the light-emitting element, the light guide plate, and the
optical sheet; and an adhesive member for fixing the display panel
to the frame, and the restriction member is bonded to the adhesive
member. According to this configuration, it is easily possible to
prevent the restriction member from being moved relative to the
frame, the light guide plate, and the like.
[0028] In the above-described backlight device according to the
first aspect, preferably, there is further provided a resinous
frame that houses the light-emitting element, the light guide
plate, and the optical sheet, and the restriction member is formed
integrally with the frame. According to this configuration, it is
easily possible to prevent the restriction member from being moved
relative to the light guide plate and the like. Furthermore,
compared with a case where the restriction member is formed as a
separate body from the frame, the number of components used can be
reduced, and the assembly process can be simplified.
[0029] In the above-described backlight device according to the
first aspect, preferably, the restriction member is fixed to the
optical sheet. According to this configuration, the restriction
member can be prevented from being moved relative to the optical
sheet, and the positional accuracy of the restriction member with
respect to the light guide plate can be improved.
[0030] In the above-described backlight device in which the
restriction member is fixed to the optical sheet, it is also
possible that the optical sheet is configured to include a
diffusion sheet disposed in contact with the light output surface
of the light guide plate, and the restriction member is fixed to
the diffusion sheet.
[0031] In the above-described backlight device according to the
first aspect, preferably, the restriction member is formed by
bonding a wide sheet member disposed forward of the light incidence
surface and the light output surface of the light guide plate to a
narrow sheet member disposed forward of the light output surface of
the light guide plate. According to this configuration, simply by
bonding the wide sheet member to the narrow sheet member, the
restriction member can be formed so as to have a cross section of,
for example, an L shape. Thus, compared with a case where the
restriction member is formed so as to have an L-shaped cross
section by, for example, resin molding using a mold, the
restriction member having an L-shaped cross section can be easily
formed. Furthermore, the wide sheet member of the restriction
member is disposed forward of the light incidence surface and the
light output surface of the light guide plate, and thus, even in a
case where, for example, an adhesive member is disposed forward of
the light guide plate, it is possible to prevent the light guide
plate from being bonded to the adhesive member. This can prevent
light incident on the light guide plate from being outputted to the
side of the adhesive member to be absorbed by the adhesive member,
and thus it is possible to suppress deterioration in light use
efficiency that leads to a decrease in the luminance of the display
panel. If the light guide plate is bonded to the adhesive member,
light incident on the light guide plate is likely to be outputted
from a portion of the light guide plate where the light guide plate
is bonded to the adhesive member. Light outputted from the light
guide plate then is absorbed by the adhesive member. Because of
this, light use efficiency is deteriorated, which leads to a
decrease in the luminance of the display panel.
[0032] In the above-described backlight device in which the
restriction member is formed by the wide sheet member and the
narrow sheet member, preferably, there is further provided a frame
that houses the light-emitting element, the light guide plate, and
the optical sheet, and the frame has a function of preventing the
wide sheet member of the restriction member from being moved in the
plane direction of the wide sheet member. According to this
configuration, it is easily possible to prevent the restriction
member from being moved in the plane direction.
[0033] In the above-described backlight device according to the
first aspect, preferably, the restriction member has a function of
reflecting light. According to this configuration, light outputted
from the inclined surface of the light guide plate can be reflected
by the restriction member, and thus light outputted from the
inclined surface of the light guide plate can be made incident
again on the light guide plate. Thus, light use efficiency can be
improved, which leads to an increase in the luminance of the
display panel.
[0034] In the above-described backlight device according to the
first aspect, preferably, there are further provided: a frame that
houses the light-emitting element, the light guide plate, and the
optical sheet; and an adhesive member for fixing the display panel
to the frame. Further, at least part of the adhesive member is
disposed forward of the light incidence surface of the light guide
plate, and a distance between the light output surface of the light
guide plate or the optical sheet and the restriction member is
smaller than a distance between the portion of the light guide
plate on the side of the light incidence surface and the adhesive
member. According to this configuration, it is possible to prevent
an increase in the distance between the light output surface of the
light guide plate or the optical sheet and the restriction member,
and thus the light guide plate can be easily restricted from being
moved in the thickness direction of the light guide plate. Thus, it
is easily possible to prevent the light guide plate as a whole from
being inclined with respect to the display panel, so that
deterioration in uniformity ratio can be easily suppressed.
[0035] In the above-described backlight device according to the
first aspect, preferably, the light-emitting element includes: a
light-emitting chip; a package main body portion that has a concave
portion for housing the light-emitting chip; and a filler that is
filled in the concave portion of the package main body portion so
as to cover the light-emitting chip. Further, the light incidence
surface of the light guide plate is formed so as to extend to a
position more forward than the concave portion of the package main
body portion. According to this configuration, an increased
proportion of light outputted from the light-emitting element can
be made incident on the light guide plate. Thus, the luminance of
the display panel can be further improved.
[0036] A display device according to a second aspect of this
invention includes: the backlight device having any of the
above-described configurations; and a display panel that is
illuminated by the backlight device. According to this
configuration, the display device that can suppress deterioration
in uniformity ratio can be obtained.
ADVANTAGEOUS EFFECTS OF THE INVENTION
[0037] As described thus far, according to the present invention,
it is easily possible to obtain a backlight device that can
suppress deterioration in uniformity ratio, and a display device
provided with the same.
BRIEF DESCRIPTION OF DRAWINGS
[0038] FIG. 1 An exploded perspective view showing the structure of
a liquid crystal display device provided with a backlight device
according to a first embodiment of the present invention.
[0039] FIG. 2 A cross-sectional view showing the structure of the
liquid crystal display device provided with the backlight device
according to the first embodiment of the present invention, which
is shown in FIG. 1.
[0040] FIG. 3 A plan view showing the structures of a frame,
optical sheets, and a restriction member of the backlight device
shown in FIG. 1.
[0041] FIG. 4 A plan view showing the structure of the frame of the
backlight device shown in FIG. 1.
[0042] FIG. 5 An exploded perspective view showing the structure of
a liquid crystal display device provided with a backlight device
according to a second embodiment of the present invention.
[0043] FIG. 6 A cross-sectional view showing the structure of the
liquid crystal display device provided with the backlight device
according to the second embodiment of the present invention, which
is shown in FIG. 5.
[0044] FIG. 7 A plan view showing the structure of a frame of the
backlight device shown in FIG. 5.
[0045] FIG. 8 An exploded perspective view showing the structure of
a liquid crystal display device provided with a backlight device
according to a third embodiment of the present invention.
[0046] FIG. 9 A cross-sectional view showing the structure of the
liquid crystal display device provided with the backlight device
according to the third embodiment of the present invention, which
is shown in FIG. 8.
[0047] FIG. 10 A cross-sectional view showing the structure of a
display device provided with a sidelight type backlight device
according to a conventional example.
DESCRIPTION OF EMBODIMENTS
First Embodiment
[0048] Referring to FIGS. 1 to 4, the following describes the
structure of a liquid crystal display device 1 provided with a
backlight device 10 according to a first embodiment of the present
invention. The liquid crystal display device 1 is an example of the
"display device" of the present invention.
[0049] The liquid crystal display device 1 provided with the
backlight device 10 according to the first embodiment of the
present invention is used in electronic equipment such as a mobile
telephone. Furthermore, as shown in FIG. 1, the liquid crystal
display device 1 is composed of a liquid crystal display panel 2,
an upper polarization plate 3 and a lower polarization plate 4 (see
FIG. 2) sandwiching the liquid crystal display panel 2
therebetween, the backlight device 10 disposed on a back surface
side (lower side) of the liquid crystal display panel 2, and a
metal frame 5 covering a back surface side portion of the backlight
device 10. The liquid crystal display panel 2 is an example of the
"display panel" of the present invention.
[0050] As shown in FIG. 2, the liquid crystal display panel 2
includes a transparent AM substrate (active matrix substrate) 2a
and a transparent opposed substrate 2b that is disposed in
opposition to the AM substrate 2a and has an area smaller than that
of the AM substrate 2a. Furthermore, liquid crystal, which is not
shown, is sealed in between the AM substrate 2a and the opposed
substrate 2b. The liquid crystal display panel 2 is illuminated by
the backlight device 10 and thereby functions as a display
panel.
[0051] A driving IC 6 and an FPC 7 are attached to the front
surface of the AM substrate 2a. The FPC 7 is bent at a
predetermined position thereof so as to be disposed also on a back
surface side of an after-mentioned frame 16. Furthermore, as shown
in FIG. 1, a connector member 8 for establishing electrical
connection with the exterior is attached to an end portion of the
FPC 7.
[0052] Furthermore, as shown in FIGS. 1 and 2, the liquid crystal
display panel 2 is bonded (fixed) to the front surface of the
after-mentioned frame 16 by use of an after-mentioned adhesive
member 19 made of a double-sided adhesive tape or the like.
[0053] In the first embodiment, as shown in FIG. 2, the backlight
device 10 is a sidelight type (edge-light type) backlight device
and includes a plurality of LEDs 11, a light guide plate 12 having
a light incidence surface 12a on which light from the LEDs 11
becomes incident, a restriction member 13 and a plurality of
optical sheets 14 that are disposed in opposition to a light output
surface 12b of the light guide plate 12, a reflection sheet 15
disposed on a back surface side of the light guide plate 12, and
the resinous frame 16 that houses these components. The LEDs 11 are
an example of the "light-emitting element" of the present
invention.
[0054] The plurality of LEDs 11 are fixed to the FPC 7 via a solder
layer 17. Furthermore, the plurality of LEDs 11 are disposed at a
predetermined pitch in an A direction (see FIG. 3) so as to be
opposed to the light incidence surface 12a of the light guide plate
12.
[0055] Furthermore, each of the LEDs 11 is composed of a blue
light-emitting chip 11a, a package main body portion 11c having a
concave portion 11b for housing the blue light-emitting chip 11a,
and a filler 11d filled in the concave portion 11b of the package
main body portion 11c so as to cover the blue light-emitting chip
11a. The filler 11d is made of a transparent resin containing a
fluorescent material and the like. The blue light-emitting chip 11a
is an example of the "light-emitting chip" of the present
invention.
[0056] A portion of the FPC 7, which is disposed on the back
surface side of the frame 16, is bonded to the back surface of the
frame 16 by use of an adhesive member 18 made of a double-sided
adhesive tape or the like.
[0057] As shown in FIG. 1, the adhesive member 18 includes one
FPC-bonding portion 18a and three metal frame-bonding portions 18b,
18c, and 18d. The FPC-bonding portion 18a bonds the frame 16 to the
FPC 7. Furthermore, the three metal frame-bonding portions 18b,
18c, and 18d bond the frame 16 to the metal frame 5.
[0058] As shown in FIG. 2, the light guide plate 12 is disposed at
a predetermined distance from the after-mentioned adhesive member
19. Furthermore, the light guide plate 12 is formed so that the
light incidence surface 12a and the light output surface 12b extend
in directions orthogonal to each other, respectively. Furthermore,
the light guide plate 12 has a function of making light from the
LEDs 11 incident from the light incidence surface 12a and
outputting the light from the light output surface 12b toward the
side of the liquid crystal display panel 2 (C1 direction).
[0059] Furthermore, an inclined surface 12c inclined at an angle
.theta. 1 (e.g. 12.degree.) with respect to the light output
surface 12b is formed between the light incidence surface 12a and
the light output surface 12b of the light guide plate 12. That is,
the light guide plate 12 is formed so as to have a thickness larger
at a portion on the side of the light incidence surface 12a (side
of the LEDs 11) than at a portion on the side of the light output
surface 12b. Specifically, the light guide plate 12 has a thickness
of, for example, 0.6 mm at the portion on the side of the light
incidence surface 12a (side of the LEDs 11) and a thickness of, for
example, 0.42 mm at the portion on the side of the light output
surface 12b.
[0060] Furthermore, the light incidence surface 12a of the light
guide plate 12 is formed so as to extend to a position more forward
(C1 direction) than the concave portion 11b of the package main
body portion 11c of each of the LEDs 11.
[0061] Furthermore, in the first embodiment, the restriction member
13 is in white color and has a function of reflecting light and a
light-blocking property. Furthermore, the restriction member 13 is
disposed forward (C1 direction) of a portion of the light output
surface 12b of the light guide plate 12 on the side of the LEDs 11
(side of a B1 direction).
[0062] Furthermore, in the first embodiment, the restriction member
13 is composed of a wide sheet member 13a disposed forward of the
light incidence surface 12a, the inclined surface 12c, and the
light output surface 12b of the light guide plate 12, a narrow
sheet member 13b disposed forward of the light output surface 12b
of the light guide plate 12, and an adhesive member 13c that bonds
together the wide sheet member 13a and the narrow sheet member 13b.
The restriction member 13 therefore has an L-shaped cross
section.
[0063] Furthermore, the wide sheet member 13a and the narrow sheet
member 13b are made of an identical material (e.g. a resin such as
PET (polyethylene terephthalate)) and are identical in
thickness.
[0064] Furthermore, in the first embodiment, the restriction member
13 has a function of restricting the light guide plate 12 from
being moved in the thickness direction of the light guide plate 12
(C direction). Specifically, the wide sheet member 13a (restriction
member 13) is bonded (fixed) to the after-mentioned adhesive member
19. Furthermore, the restriction member 13 is formed so that a
distance (e.g. several tens of .mu.m) between the light output
surface 12b of the light guide plate 12 (an after-mentioned
diffusion sheet 14a among the optical sheets 14) and the narrow
sheet member 13b of the restriction member 13 is smaller than a
distance between the portion of the light guide plate 12 on the
side of the light incidence surface 12a and the wide sheet member
13a of the restriction member 13 or the adhesive member 19. Thus,
the light guide plate 12 is restricted from being moved in the
thickness direction (C direction).
[0065] The plurality of optical sheets 14 are composed of the
diffusion sheet 14a that is disposed in contact with the light
guide plate 12 and has a function of diffusing light, and a lower
lens sheet 14b and an upper lens sheet 14c that are disposed
forward (C1 direction) of the diffusion sheet 14a and have a
function of condensing light.
[0066] The reflection sheet 15 has a function of reflecting light
outputted from the back surface of the light guide plate 12 and
making the light travel to the side of the light guide plate 12 (C1
direction).
[0067] The frame 16 houses the plurality of LEDs 11, the light
guide plate 12, the plurality of optical sheets 14, and the like.
Furthermore, as shown in FIG. 4, the frame 16 has an opening 16a
and is formed in the shape of a frame defined by long side portions
16b and 16c and short side portions 16d and 16e.
[0068] As shown in FIG. 3, the plurality of optical sheets 14 are
disposed in a portion surrounded by the long side portion 16c and
the short side portions 16d and 16e. This can prevent the optical
sheets 14 from being moved in the plane direction (A direction and
B direction). Similarly to the optical sheets 14, the light guide
plate 12 is also prevented from being moved in the plane direction
(A direction and B direction).
[0069] Furthermore, the restriction member 13 is disposed at a
portion of the opening 16a on the side of the long side portion
16b. The portion of the opening 16a on the side of the long side
portion 16b is formed in substantially the same shape as the wide
sheet member 13a of the restriction member 13.
[0070] Furthermore, in the first embodiment, the long side portion
16b of the frame 16 has a function of preventing (restricting) the
wide sheet member 13a of the restriction member 13 from being moved
in the plane direction (A direction and B1 direction), and the
optical sheets 14 (lower lens sheet 14b and upper lens sheet 14c)
have a function of preventing (restricting) the wide sheet member
13a of the restriction member 13 from being moved in the plane
direction (B2 direction).
[0071] Specifically, in assembling the backlight device 10, as
shown in FIG. 2, in a state where the light guide plate 12 and the
plurality of optical sheets 14 are disposed in the opening 16a of
the frame 16, the restriction member 13 is disposed forward (C1
direction) of the light guide plate 12. At this time, as shown in
FIG. 3, the long side portion 16b of the frame 16 prevents
(restricts) the wide sheet member 13a of the restriction member 13
from being moved in the plane direction (A direction and B1
direction). Furthermore, at this time, the lower lens sheet 14b and
the upper lens sheet 14c among the optical sheets 14 prevent
(restrict) the wide sheet member 13a of the restriction member 13
from being moved in the plane direction (B2 direction). In this
manner, the positioning of the restriction member 13 is achieved.
Then, in a state where the position of the restriction member 13 is
thus set, the adhesive member 19 is bonded to the frame 16 and the
restriction member 13, and the restriction member 13 is thereby
fixed.
[0072] Furthermore, as shown in FIG. 1, the adhesive member 19 that
bonds (fixes) the frame 16 to the liquid crystal display panel 2
has an opening 19a and is formed in the shape of a frame defined by
long side portions 19b and 19c and short side portions 19d and
19e.
[0073] The long side portion 19b has a width larger than that of
the long side portion 16b of the frame 16. Furthermore, as shown in
FIG. 2, the long side portion 19b is disposed so as to extend to a
position forward of the light incidence surface 12a, the inclined
surface 12c, and the light output surface 12b of the light guide
plate 12.
[0074] In the first embodiment, as described in the foregoing, the
restriction member 13 having a light-blocking property is disposed
forward (C1 direction) of the portion of the light output surface
12b of the light guide plate 12 on the side of the light incidence
surface 12a (side of the LEDs 11). Thus, even in a case where part
of light incident on the light guide plate 12 is outputted from the
inclined surface 12c to the side of the liquid crystal display
panel 2, it is possible to prevent light outputted from the light
guide plate 12 from reaching the liquid crystal display panel 2.
This can prevent a phenomenon in which the liquid crystal display
panel 2 exhibits a high (increased) luminance at a portion thereof
in the vicinity of the LEDs 11 compared with a luminance at a
portion thereof other than the vicinity of the LEDs 11. As a
result, deterioration in uniformity ratio can be suppressed.
[0075] Furthermore, in the first embodiment, as described in the
foregoing, the restriction member 13 that restricts the light guide
plate 12 from being moved in the thickness direction of the light
guide plate 12 (C direction) is disposed forward of the portion of
the light output surface 12b of the light guide plate 12 on the
side of the light incidence surface 12a (side of the LEDs 11), and
thus the light guide plate 12 can be prevented from being moved in
the thickness direction. This can prevent the light guide plate 12
as a whole from being inclined with respect to the liquid crystal
display panel 2, and thus a phenomenon can be prevented in which
the liquid crystal display panel 2 exhibits a high luminance at a
portion thereof on the side of the LEDs 11 (a low luminance at a
portion thereof on the side opposite to the LEDs 11), or a low
luminance at the portion thereof on the side of the LEDs 11 (a high
luminance at the portion thereof on the side opposite to the LEDs
11). As a result, deterioration in uniformity ratio can be further
suppressed.
[0076] Furthermore, in the first embodiment, as described in the
foregoing, the light guide plate 12 is formed so as to have a
thickness larger at the portion on the side of the light incidence
surface 12a than at the portion on the side of the light output
surface 12b, and thus the area of the light incidence surface 12a
can be increased. Thus, an increased proportion of light outputted
from the LEDs 11 can be made incident on the light guide plate 12,
so that the luminance of the liquid crystal display panel 2 can be
improved.
[0077] Furthermore, in the first embodiment, as described in the
foregoing, the light guide plate 12 is formed so as to have a
thickness larger at the portion on the side of the light incidence
surface 12a than at the portion on the side of the light output
surface 12b, and thus the light guide plate 12 can be made thinner
at the portion thereof on the side of the light output surface 12b,
thereby allowing a reduction in the thickness of the backlight
device 10 (liquid crystal display device 1) as a whole.
[0078] Furthermore, in the first embodiment, as described in the
foregoing, the restriction member 13 is fixed (bonded) to the
adhesive member 19, and thus it is easily possible to prevent the
restriction member 13 from being moved relative to the frame 16,
the light guide plate 12, and the like.
[0079] Furthermore, in the first embodiment, as described in the
foregoing, the restriction member 13 is formed by bonding the wide
sheet member 13a to the narrow sheet member 13b, and thus, simply
by bonding the wide sheet member 13a to the narrow sheet member
13b, the restriction member 13 can be formed so as to have an
L-shaped cross section. Thus, compared with a case where the
restriction member 13 is formed so as to have an L-shaped cross
section by, for example, resin molding using a mold, the
restriction member 13 having an L-shaped cross section can be
easily formed. Furthermore, the wide sheet member 13a of the
restriction member 13 is disposed forward of the light incidence
surface 12a and the light output surface 12b of the light guide
plate 12, and thus it is possible to prevent the light guide plate
12 from being bonded to the adhesive member 19. This can prevent
light incident on the light guide plate 12 from being outputted to
the side of the adhesive member 19 to be absorbed by the adhesive
member 19, and thus it is possible to suppress deterioration in
light use efficiency that leads to a decrease in the luminance of
the liquid crystal display panel 2. If the light guide plate 12 is
bonded to the adhesive member 19, light incident on the light guide
plate 12 is likely to be outputted from a portion of the light
guide plate 12 where the light guide plate 12 is bonded to the
adhesive member 19. Light outputted from the light guide plate 12
then is absorbed by the adhesive member 19. Because of this, light
use efficiency is deteriorated, which leads to a decrease in the
luminance of the liquid crystal display panel 2.
[0080] Furthermore, in the first embodiment, as described in the
foregoing, the long side portion 16b of the frame 16 is configured
to have a function of preventing (restricting) the wide sheet
member 13a of the restriction member 13 from being moved in the
plane direction (A direction and B direction), and thus, at the
time of assembly, it is easily possible to prevent the restriction
member 13 from being moved in the plane direction. This can
facilitate assembling the backlight device 10.
[0081] Furthermore, in the first embodiment, as described in the
foregoing, the restriction member 13 is formed in white color, and
thus, compared with a case where the restriction member 13 is in,
for example, black color, the light reflectivity of the restriction
member 13 can be increased. As a result of this, an increased
proportion of light outputted from the inclined surface 12c of the
light guide plate 12 can be reflected by the restriction member 13,
and thus an increased proportion of light outputted from the
inclined surface 12c of the light guide plate 12 can be made
incident again on the light guide plate 12. Thus, light use
efficiency can be improved, which leads to an increase in the
luminance of the liquid crystal display panel 2.
[0082] Furthermore, in the first embodiment, as described in the
foregoing, the light incidence surface 12a of the light guide plate
12 is formed so as to extend to a position more forward than the
concave portion 11b of the package main body portion 11c, and thus
an increased proportion of light outputted from the LEDs 11 can be
made incident on the light incidence surface 12a of the light guide
plate 12. This can further improve the luminance of the liquid
crystal display panel 2.
[0083] Furthermore, in the first embodiment, as described in the
foregoing, the wide sheet member 13a and the narrow sheet member
13b are made of an identical material and are identical in
thickness. The wide sheet member 13a and the narrow sheet member
13b can therefore be formed using an identical material (sheet
member), and thus the manufacturing cost can be reduced.
[0084] Next, the following describes comparative experiments
performed to confirm the effects of the liquid crystal display
device 1 provided with the backlight device 10 according to the
foregoing first embodiment of the present invention. These
comparative experiments used a liquid crystal display device
according to a working example corresponding to the foregoing first
embodiment and a liquid crystal display device according to a
comparative example that, unlike the above-described working
example, did not include a restriction member. The comparative
experiments thus were performed with respect to the liquid crystal
display devices according to the working example and the
comparative example, respectively.
[0085] The description is directed first to the experiment in which
a comparison of the uniformity ratio was made between the liquid
crystal display devices according to the working example and the
comparative example, respectively. In this comparative experiment,
30 units of each of the liquid crystal display devices according to
the working example and the comparative example, respectively, were
prepared as samples. The liquid crystal display device according to
the comparative example had the same structure as that of the
liquid crystal display device according to the working example,
except that it did not include a restriction member.
[0086] With respect to each of the samples of the liquid crystal
display devices, luminance values at nine points (Points P1 to P9
in FIG. 1) on the liquid crystal display panel 2 (upper
polarization plate 3) were measured, and the maximum value of the
luminance values thus measured at the nice points (Points P1 to P9)
was divided by the minimum value of the thus measured luminance
values to determine a uniformity ratio. With respect to the 30
units of each of the liquid crystal display devices according to
the working example and the comparative example, respectively, the
mean value, the maximum value, and the minimum value of the
uniformity ratios thus determined are shown in Table 1 below.
TABLE-US-00001 TABLE 1 Uniformity Ratio of Uniformity Ratio of
Working Example Comparative Example Mean Value 1.13 1.21 Maximum
Value 1.19 1.37 Minimum Value 1.10 1.12 Standard 0.03 0.06
Deviation
[0087] As shown in Table 1 above, it was found that, compared with
the liquid crystal display device according to the comparative
example, the liquid crystal display device according to the working
example has an improved uniformity ratio (approximate to 1).
Specifically, the samples of the liquid crystal display device
according to the working example exhibited uniformity ratios with a
mean value of about 1.13, a maximum value of about 1.19, a minimum
value of about 1.10, and a standard deviation of about 0.03. On the
other hand, the samples of the liquid crystal display device
according to the comparative example exhibited uniformity ratios
with a mean value of about 1.21, a maximum value of about 1.37, a
minimum value of about 1.12, and a standard deviation of about
0.06.
[0088] Conceivably, these results are attributable to the
following. That is, in the liquid crystal display device according
to the working example, the restriction member 13 having a
light-blocking property was disposed forward of the portion of the
light output surface 12b of the light guide plate 12 on the side of
the light incidence surface 12a (side of the LEDs 11), and thus,
even in a case where part of light incident on the light guide
plate 12 was outputted from the inclined surface 12c to the side of
the liquid crystal display panel 2, it was possible to prevent
light outputted from the light guide plate 12 from reaching the
liquid crystal display panel 2. This could prevent a phenomenon in
which the liquid crystal display panel 2 exhibits a high
(increased) luminance at a portion thereof in the vicinity of the
LEDs 11 compared with a luminance at a portion thereof other than
the vicinity of the LEDs 11. This conceivably led to an improvement
in uniformity ratio.
[0089] Furthermore, in the liquid crystal display device according
to the working example, the restriction member 13 that restricted
the light guide plate 12 from being moved in the thickness
direction (C direction) was disposed forward of the portion of the
light output surface 12b of the light guide plate 12 on the side of
the light incidence surface 12a (side of the LEDs 11), and thus the
light guide plate 12 could be prevented from being moved in the
thickness direction. This could prevent the light guide plate 12 as
a whole from being inclined with respect to the liquid crystal
display panel 2, and thus a phenomenon could be prevented in which
the liquid crystal display panel 2 exhibits a high luminance at a
portion thereof on the side of the LEDs 11 (a low luminance at a
portion thereof on the side opposite to the LEDs 11), or a low
luminance at the portion thereof on the side of the LEDs 11 (a high
luminance at the portion thereof on the side opposite to the LEDs
11). This conceivably led to a further improvement in uniformity
ratio.
[0090] Furthermore, in the liquid crystal display device according
to the working example, the light guide plate 12 could be prevented
from being moved in the thickness direction, and thus variations in
the amount of light entering the light guide plate 12 could be
prevented. This conceivably led to a decrease in the standard
deviation of the uniformity ratios (a decrease in variations).
[0091] The description is directed next to the experiment in which
a comparison of luminance was made between the liquid crystal
display devices according to the working example and the
comparative example, respectively. In this comparative experiment,
a luminance value on the center (Point P5 in FIG. 1) of the liquid
crystal display panel 2 (upper polarization plate 3) was compared
between the liquid crystal display devices according to the working
example and the comparative example, respectively. Specifically,
with respect to the 30 units of each of the liquid crystal display
devices according to the working example and the comparative
example, respectively, a mean luminance value was determined based
on the respective luminance values at Point P5 measured in the
above-described comparative experiment for a comparison of the
uniformity ratio.
[0092] In this comparative experiment, it was found that, compared
with the liquid crystal display device according to the comparative
example, the liquid crystal display device according to the working
example has improved luminance. Specifically, the samples of the
liquid crystal display device according to the working example
exhibited a mean luminance value of about 296 (cd/m.sup.2). On the
other hand, the samples of the liquid crystal display device
according to the comparative example exhibited a mean luminance
value of about 292 (cd/m.sup.2).
[0093] Conceivably, these results are attributable to the
following. That is, in the liquid crystal display device according
to the working example, the restriction member 13 was formed so as
to have a function of reflecting light, and thus light outputted
from the inclined surface 12c of the light guide plate 12 could be
reflected by the restriction member 13, so that light outputted
from the inclined surface 12c of the light guide plate 12 could be
made incident again on the light guide plate 12. This is
conceivably the reason that light use efficiency could be improved,
which led to an increase in the luminance of the liquid crystal
display panel 2.
Second Embodiment
[0094] Referring to FIGS. 5 to 7, this second embodiment describes
a case where, unlike the previously described first embodiment, a
restriction portion (restriction member) 116g is formed integrally
with a frame 116.
[0095] In a backlight device 110 of a liquid crystal display device
101 according to the second embodiment of the present invention, as
shown in FIGS. 5 and 7, the resinous frame 116 has two openings
116a and 116b. Furthermore, the frame 116 is formed in the shape of
a frame defined by long side portions 116c and 116d and short side
portions 116e and 116f.
[0096] Furthermore, in the second embodiment, as shown in FIG. 7,
the restriction portion 116g is formed integrally with the long
side portion 116c of the frame 116, and the opening 116a and the
opening 116b are separated from each other by the restriction
portion 116g. The restriction portion 116g is an example of the
"restriction member" of the present invention.
[0097] Furthermore, as shown in FIG. 6, similarly to the previously
described first embodiment, the restriction portion 116g is
disposed in opposition to a light output surface 12b of a light
guide plate 12. Furthermore, the restriction portion 116g (frame
116) is in white color and has a function of reflecting light and a
light-blocking property.
[0098] Furthermore, similarly to the previously described first
embodiment, the restriction portion 116g has a function of
restricting the light guide plate 12 from being moved in the
thickness direction of the light guide plate 12 (C direction).
Specifically, the restriction portion 116g is formed so that a
distance (e.g. several tens of .mu.m) between the light output
surface 12b of the light guide plate 12 (diffusion sheet 14a) and
the restriction portion 116g is smaller than a distance between a
portion of the light guide plate 12 on the side of a light
incidence surface 12a and an adhesive member 19. Thus, the light
guide plate 12 is restricted from being moved in the thickness
direction (C direction).
[0099] Furthermore, the restriction portion 116g is formed so as to
have a rectangular cross section. In the second embodiment, the
restriction portion 116g, therefore, is not disposed forward (C1
direction) of the portion of the light guide plate 12 on the side
of the light incidence surface 12b. The restriction portion 116g
may also be formed so as to have an L-shaped cross section so that
part of the restriction portion 116g is disposed forward of the
portion of the light guide plate 12 on the side of the light
incidence surface 12b. In this case, it is not required to form the
opening 116a in the frame 116.
[0100] Other components of the second embodiment are structured
similarly to those in the previously described first
embodiment.
[0101] In the second embodiment, as described in the foregoing, the
restriction portion 116g is formed integrally with the frame 116,
and thus, compared with a case where the restriction portion 116g
is formed as a separate body from the frame 116, it is easily
possible to prevent the restriction portion 116g from being moved
relative to the light guide plate 12 and the like. Furthermore, the
number of components used can be reduced, and the assembly process
can be simplified.
[0102] Other effects of the second embodiment are similar to those
of the previously described first embodiment.
Third Embodiment
[0103] Referring to FIGS. 8 and 9, this third embodiment describes
a case where, unlike the previously described first and second
embodiments, a restriction member 213 is fixed to a diffusion sheet
14a (optical sheets 14).
[0104] In a backlight device 210 of a liquid crystal display device
201 according to the third embodiment of the present invention, as
shown in FIGS. 8 and 9, the restriction member 213 is fixed
(bonded) to an end portion of the diffusion sheet 14a on the side
of LEDs 11 (B1 direction).
[0105] Specifically, the restriction member 213 is composed of a
sheet member 213a made of a resin such as, for example, white PET
and an adhesive member 213b and is formed so as to have a
rectangular cross section. The adhesive member 213b is made of a
double-sided adhesive tape or the like and has a function of fixing
the sheet member 213a to the diffusion sheet 14a.
[0106] In the third embodiment, in assembling the backlight device
210, the diffusion sheet 14a with the restriction member 213 fixed
to a predetermined position thereof is prepared beforehand. In a
state where a light guide plate 12 is disposed in an opening 16a of
a frame 16, a plurality of the optical sheets 14 (diffusion sheet
14a) are disposed forward (C1 direction) of a light output surface
12b of the light guide plate 12. At this time, since the
restriction member 213 is fixed to the diffusion sheet 14a, the
restriction member 213 is prevented (restricted) from being moved
in the plane direction (A direction and B direction).
[0107] Furthermore, in the third embodiment, the restriction member
213 is formed so as to have a rectangular cross section and,
therefore, is not disposed forward of a portion of the light guide
plate 12 on the side of a light incidence surface 12b. Similarly to
the previously described first embodiment, the restriction member
213 may also be formed so as to have an L-shaped cross section so
that part of the restriction member 213 is disposed forward of the
portion of the light guide plate 12 on the side of the light
incidence surface 12b.
[0108] Furthermore, similarly to the previously described first
embodiment, the restriction member 213 has a function of
restricting the light guide plate 12 from being moved in the
thickness direction of the light guide plate 12 (C direction).
Specifically, the restriction member 213 is formed so that a
distance (e.g. several tens of .mu.m) between the restriction
member 213 and an adhesive member 19 is smaller than a distance
between the portion of the light guide plate 12 on the side of the
light incidence surface 12a and the adhesive member 19. Thus, the
light guide plate 12 is restricted from being moved in the
thickness direction (C direction).
[0109] Other components of the third embodiment are structured
similarly to those in the previously described first
embodiment.
[0110] In the third embodiment, as described in the foregoing, the
restriction member 213 is fixed to the diffusion sheet 14a. Thus,
the restriction member 213 can be prevented from being moved
relative to the diffusion sheet 14a, and the positional accuracy of
the restriction member 213 with respect to the light guide plate 12
can be improved.
[0111] Furthermore, in the third embodiment, as described in the
foregoing, in assembling the backlight device 210, the diffusion
sheet 14a with the restriction member 213 fixed to a predetermined
position thereof is prepared beforehand and then is disposed
forward (C1 direction) of the light output surface 12b of the light
guide plate 12. Thus, simply by disposing the diffusion sheet 14a
at a predetermined position, the restriction member 213 can also be
disposed at a predetermined position, so that the assembly process
can be simplified.
[0112] Other effects of the third embodiment are similar to those
of the previously described first embodiment.
[0113] The embodiments disclosed in this application are to be
considered in all respects as illustrative and not limiting. The
scope of the present invention is indicated by the appended claims
rather than by the foregoing description of the embodiments, and
all changes which come within the meaning and range of equivalency
of the claims are intended to be embraced therein.
[0114] For example, each of the previously described embodiments
shows an example adopting a liquid crystal display device as the
display device. The present invention, however, is not limited
thereto and may be applied also to display devices of other types
than a liquid crystal display device.
[0115] Furthermore, each of the previously described embodiments
shows a case where the liquid crystal display device is used in
electronic equipment such as a mobile telephone. The present
invention, however, is not limited thereto, and the liquid crystal
display device may be used also in electronic equipment of any
other type than a mobile telephone.
[0116] Furthermore, each of the previously described embodiments
shows an example in which an LED including a blue light-emitting
chip is used as the light-emitting element. The present invention,
however, is not limited thereto, and an LED including a
light-emitting chip of any other type than a blue light-emitting
chip may also be used, or a light-emitting element of any other
type than an LED may also be used.
[0117] Furthermore, each of the previously described embodiments
shows an example using the resinous restriction member. The present
invention, however, is not limited thereto, and a restriction
member made of a material other than resin may also be used.
[0118] Furthermore, each of the previously described embodiments
shows an example in which the restriction member is formed in white
color. The present invention, however, is not limited thereto, and
the restriction member may be formed also in, for example, silver
color having a relatively high reflectivity or in, for example,
black color having a relatively low reflectivity. Furthermore, the
restriction member may also be formed so as not to have a function
of reflecting light.
[0119] Furthermore, each of the previously described embodiments
shows an example in which the restriction member is formed so as to
have a cross section of an L shape or a rectangular shape. The
present invention, however, is not limited thereto, and the
restriction member may also be formed so as to have a cross section
of, for example, a trapezoidal shape other than an L shape and a
rectangular shape.
[0120] Furthermore, the previously described first embodiment shows
an example in which the restriction member is formed by bonding the
wide sheet member to the narrow sheet member. The present
invention, however, is not limited thereto, and the restriction
member may also be formed by resin molding using a mold.
[0121] Furthermore, the previously described first embodiment shows
an example in which the restriction member is formed by bonding the
wide sheet member to the narrow sheet member, which are identical
in thickness. The present invention, however, is not limited
thereto, and the restriction member may also be formed by bonding a
wide sheet member to a narrow sheet member, which are different in
thickness.
[0122] Furthermore, each of the previously described first and
second embodiments shows an example in which the diffusion sheet is
disposed between the restriction member (restriction portion) and
the light guide plate. The present invention, however, is not
limited thereto and may also be configured so that the diffusion
sheet is reduced in length and not disposed between the restriction
member (restriction portion) and the light guide plate.
[0123] Furthermore, each of the previously described first and
second embodiments shows an example in which the restriction member
(restriction portion) is disposed at a predetermined distance from
the light guide plate and the diffusion sheet, and the previously
described third embodiment shows an example in which the
restriction member is disposed at a predetermined distance from the
adhesive member 19. The present invention, however, is not limited
thereto, and the restriction member (restriction portion) may also
be disposed in contact with the light guide plate, the diffusion
sheet, and the adhesive member 19.
[0124] Furthermore, the previously described third embodiment shows
an example in which the restriction member is fixed to the
diffusion sheet. The present invention, however, is not limited
thereto, and the restriction member may also be fixed to the upper
lens sheet, the lower lens sheet, or the like.
[0125] Furthermore, each of the previously described embodiments
shows an example in which the inclined surface of the light guide
plate is formed so as to be inclined at 12.degree. with respect to
the light output surface. The present invention, however, is not
limited thereto, and the inclined surface of the light guide plate
may also be formed so as to be inclined at an angle larger or
smaller than 12.degree. with respect to the light output
surface.
LIST OF REFERENCE SIGNS
[0126] 1, 101, 201 Liquid crystal display device (Display device)
[0127] 2 Liquid crystal display panel (Display panel) [0128] 10,
110, 210 Backlight device [0129] 11 LED (Light-emitting element)
[0130] 11a Blue light-emitting chip (Light-emitting chip) [0131]
11b Concave portion [0132] 11c Package main body portion [0133] 11d
Filler [0134] 12 Light guide plate [0135] 12a Light incidence
surface [0136] 12b Light output surface [0137] 12c Inclined surface
[0138] 13, 213 Restriction member [0139] 13a Wide sheet member
[0140] 13b Narrow sheet member [0141] 14 Optical sheet [0142] 14a
Diffusion sheet [0143] 16, 116 Frame [0144] 19 Adhesive member
[0145] 116g Restriction portion (Restriction member)
* * * * *